Printed indicia which are applied to items of clothing, such as T-shirts, sweatshirts, golf shirts, shorts, hats, and the like, as well as other cloth and paper goods, such as banners, posters, bags, flags, and the like, have become very popular over the last 20 years. Boutiques which specialize in printing fanciful and textual indicia such as slogans, college names, sports team names and logos, licensed characters, and the like, on these various media, are commonly seen in shopping malls across the country. The indicia available at these boutiques can be pre-printed on a substrate and applied with a heated press by operators at such boutiques to any of the aforementioned items purchased by a consumer, or they can be screen printed directly on the items for later purchase.
In the screen printing process, a stencil screen which has been blocked (called "masked" in the industry) to embody the desired indicia is placed over the item to be printed. Ink of one color is then flooded onto the screen (the "flood stroke") by a flood bar of conventional design. The ink may be of any type well-known in the industry for screen printing. After the ink is flooded onto the screen, the ink is squeegeed through the screen interstices onto the item (the "print stroke") leaving ink of the desired color where the interstices in the screen are unblocked. The squeegee can be of any type known in the art.
As the ink is flooded onto the screen, and during the print stroke, the ink tends to be forced to the edges of the screen between the ends of the squeegee and flood bar and the screen frame. This causes undesired ink buildup which is not utilized in the printing process and is usually wasted. To prevent this buildup, the operator must periodically scrape up the ink from the edges of the screen and place it in front of the flood bar. This is usually done while the screen printing machine is still operating, since shutting down operation can be a costly and time consuming and time consuming alternative.
The reasons for removing the ink from the edges are so the ink: (1) becomes usable and is not wasted; (2) is prevented from hardening, making cleanup especially difficult; and, (3) does not spill over the screen to ruin the object being printed upon or further dirty the screen and surrounding area. At cleanup time, the operator must clean the screen of all ink so that the screen may be reused. The ink deposits along the frame significantly increase the time required for cleanup, particularly if the ink has dried. The operator must often resort to using a spatula, putty knife, or similar object to scrape the ink from the edges of the framed screen before washing the area with solvents. Such harsh requirements can diminish the longevity of the screen.
In an attempt to automatically prevent the ink from collecting at the edges of the screen, flood bars and squeegees with integral scrapers have been developed. One such device is disclosed in U.S. Pat. No. 5,392,705 to Jaffa. The scrapers work to scrape the ink from the edges of the screen automatically while the flood bar moves along the screen during the flood stroke, and while the squeegee moves along the screen during the print stroke. The integral contoured scrapers generally work, but require the purchase of entire sets of flood bar and squeegee assemblies. This undertaking can become quite expensive since different sizes of screens and indicia are used requiring different sizes of flood bars and squeegees. Such designs also do not permit the versatility or reusability of the present invention.
U.S. Pat. No. 5,165,339 to Hoffman et al. discloses a detachable scraper attachment for a flood bar. The Hoffman et al. scraper design provides the added advantage of being detachable and capable of retrofitting existing flood bars. However, it is not capable of maintaining ink within the ink reservoir, nor does it direct ink to the center of the printing area.
Other attempts at controlling the spread of ink in a screen printing operation are disclosed in U.S. Pat. Nos.: 2,881,698 to Graham; 4,080,893 to Wedell; 4,102,266 to Porth; and 4,121,519 to Porth. The designs disclosed within these referenced patents do not solve the problems to which the present invention is specifically concerned.